The four species that she tested were Methanothermobacter wolfeii , Methanosarcina barkeri , Methanobacterium formicicum , and Methanococcus maripaludis. The Curiosity rover , which landed on Mars in August , is able to make measurements that distinguish between different isotopologues of methane, and in , Curiosity detected a "tenfold spike" in the level of methane in the Martian atmosphere compared to the usual background readings. Four measurements taken over two months in this period averaged 7 ppb, suggesting that methane is released at intervals. That's a huge change, completely unexpected.
And what it does, it gives us a key to unlocking the mysteries associated with Mars methane because now we have something to test our models and our understanding against. He also says " The ExoMars Trace Gas Orbiter , launched in March , began on 21 April to map the concentration and sources of methane in the atmosphere,   as well as its decomposition products such as formaldehyde and methanol.
Vittorio Formisano, the director of the PFS, has speculated that the formaldehyde could be the byproduct of the oxidation of methane and, according to him, would provide evidence that Mars is either extremely geologically active or harboring colonies of microbial life. The s Viking program placed two identical landers on the surface of Mars tasked to look for biosignatures of microbial life on the surface.
Of the four experiments performed by each Viking lander, only the 'Labeled Release' LR experiment gave a positive result for metabolism , while the other three did not detect organic compounds. The LR was a specific experiment designed to test only a narrowly defined critical aspect of the theory concerning the possibility of life on Mars; therefore, the overall results were declared inconclusive.
The claim of extant microbial life on Mars is based on old data collected by the Viking landers, currently reinterpreted as sufficient evidence of life, mainly by Gilbert Levin ,  Joseph D. The study determined that perchlorate —discovered in by Phoenix lander   — can destroy organic compounds when heated, and produce chloromethane and dichloromethane as a byproduct, the identical chlorine compounds discovered by both Viking landers when they performed the same tests on Mars.
Because perchlorate would have broken down any Martian organics, the question of whether or not Viking found organic compounds is still wide open. The Labeled Release evidence was not generally accepted initially, and, to this day lacks the consensus of the scientific community. In June , NASA reported that the Curiosity rover had found evidence of complex organic compounds from mudstone rocks aged approximately 3. The rock samples, when pyrolyzed via the Curiosity ' s Sample Analysis at Mars instrument, released an array of organic molecules; these include sulfur-containing thiophenes , aromatic compounds such as benzene and toluene , and aliphatic compounds such as propane and butene.
The concentration of organic compounds is fold higher than earlier measurements. The authors speculate that the presence of sulfur may have helped preserve them. The products resemble those obtained from the breakdown of kerogen , a precursor to oil and natural gas on Earth. NASA stated that these findings are not evidence that life existed on the planet, but that the organic compounds needed to sustain microscopic life were present and there may be deeper sources of organic compounds on the planet.
There are 34 known Martian meteorites some of which were found in several fragments. Some researchers have argued that microscopic morphological features found in ALH are biomorphs , however this interpretation has been highly controversial and is not supported by the majority of researchers in the field. Seven criteria have been established for the recognition of past life within terrestrial geologic samples.
For general acceptance of past life in a geologic sample, essentially most or all of these criteria must be met. All seven criteria have not yet been met for any of the Martian samples. In , the Martian meteorite ALH , a specimen that is much older than the majority of Martian meteorites that have been recovered so far, received considerable attention when a group of NASA scientists led by David S. McKay reported microscopic features and geochemical anomalies that they considered to be best explained by the rock having hosted Martian bacteria in the distant past.
Some of these features resembled terrestrial bacteria, aside from their being much smaller than any known form of life. Much controversy arose over this claim, and ultimately all of the evidence McKay's team cited as evidence of life was found to be explainable by non-biological processes.
Although the scientific community has largely rejected the claim ALH contains evidence of ancient Martian life, the controversy associated with it is now seen as a historically significant moment in the development of exobiology. Researchers found preterrestrial aqueous alteration phases and objects  of the size and shape consistent with Earthly fossilized nanobacteria. This caused additional interest in this meteorite, so in , NASA managed to obtain an additional and larger sample from the London Natural History Museum.
On this second sample, a large dendritic carbon content was observed. When the results and evidence were published in , some independent researchers claimed that the carbon deposits are of biologic origin. It was remarked that since carbon is the fourth most abundant element in the Universe , finding it in curious patterns is not indicative or suggestive of biological origin. Certain features in its interior suggest remnants of a biofilm and its associated microbial communities.
Yamato is the second largest meteorite from Mars found on Earth. Studies suggest the Martian meteorite was formed about 1. An impact occurred on Mars about 12 million years ago and ejected the meteorite from the Martian surface into space. The meteorite landed on Earth in Antarctica about 50, years ago. The mass of the meteorite is The carbon-rich spheres may have been formed by biotic activity according to NASA scientists. The seasonal frosting and defrosting of the southern ice cap results in the formation of spider-like radial channels carved on 1-meter thick ice by sunlight.
Then, sublimed CO 2 — and probably water — increase pressure in their interior producing geyser-like eruptions of cold fluids often mixed with dark basaltic sand or mud. A team of Hungarian scientists propose that the geysers' most visible features, dark dune spots and spider channels, may be colonies of photosynthetic Martian microorganisms, which over-winter beneath the ice cap, and as the sunlight returns to the pole during early spring, light penetrates the ice, the microorganisms photosynthesize and heat their immediate surroundings.
A pocket of liquid water, which would normally evaporate instantly in the thin Martian atmosphere, is trapped around them by the overlying ice. As this ice layer thins, the microorganisms show through grey.
When the layer has completely melted, the microorganisms rapidly desiccate and turn black, surrounded by a grey aureole. Clarke promoted these formations as deserving of study from an astrobiological perspective. A multinational European team suggests that if liquid water is present in the spiders' channels during their annual defrost cycle, they might provide a niche where certain microscopic life forms could have retreated and adapted while sheltered from solar radiation.
Mars The Living Planet and millions of other books are available for Amazon Kindle. It was in this book (published on 07/23/97) that Dr. Gilbert V. Levin first announced his conclusion that his Viking Labeled Release (LR) life detection experiment flown on NASA's Viking. Editorial Reviews. From Kirkus Reviews. Claims of Martian life continue to spur scientific Mars The Living Planet - Kindle edition by Barry E. DiGregorio.
Planetary protection of Mars aims to prevent biological contamination of the planet. There is abundant evidence as to what can happen when organisms from regions on Earth that have been isolated from one another for significant periods of time are introduced into each other's environment.
Species that are constrained in one environment can thrive — often out of control — in another environment much to the detriment of the original species that were present. In some ways, this problem could be compounded if life forms from one planet were introduced into the totally alien ecology of another world. The prime concern of hardware contaminating Mars derives from incomplete spacecraft sterilization of some hardy terrestrial bacteria extremophiles despite best efforts. This has prompted research on survival rates of radiation-resistant microorganisms including the species Deinococcus radiodurans and genera Brevundimonas , Rhodococcus , and Pseudomonas under simulated Martian conditions.
On 26 April , scientists reported that an extremophile lichen survived and showed remarkable results on the adaptation capacity of photosynthetic activity within the simulation time of 34 days under Martian conditions in the Mars Simulation Laboratory MSL maintained by the German Aerospace Center DLR.
Although numerous studies point to resistance to some of Mars conditions, they do so separately, and none has considered the full range of Martian surface conditions, including temperature, pressure, atmospheric composition, radiation, humidity, oxidizing regolith, and others, all at the same time and in combination.
Mars-1 was the first spacecraft launched to Mars in ,  but communication was lost while en route to Mars. With Mars-2 and Mars-3 in , information was obtained on the nature of the surface rocks and altitude profiles of the surface density of the soil, its thermal conductivity, and thermal anomalies detected on the surface of Mars. No signs of life were found. Mariner 4 probe performed the first successful flyby of the planet Mars, returning the first pictures of the Martian surface in The photographs showed an arid Mars without rivers, oceans, or any signs of life.
Further, it revealed that the surface at least the parts that it photographed was covered in craters, indicating a lack of plate tectonics and weathering of any kind for the last 4 billion years. The probe also found that Mars has no global magnetic field that would protect the planet from potentially life-threatening cosmic rays.
The probe was able to calculate the atmospheric pressure on the planet to be about 0. Liquid water is necessary for known life and metabolism , so if water was present on Mars, the chances of it having supported life may have been determinant. The Viking orbiters found evidence of possible river valleys in many areas, erosion and, in the southern hemisphere, branched streams. The primary mission of the Viking probes of the mids was to carry out experiments designed to detect microorganisms in Martian soil because the favorable conditions for the evolution of multicellular organisms ceased some four billion years ago on Mars.
Of the four experiments, only the Labeled Release LR experiment returned a positive result, [ dubious — discuss ] showing increased 14 CO 2 production on first exposure of soil to water and nutrients. All scientists agree on two points from the Viking missions: There are vastly different interpretations of what those results imply.
A astrobiology textbook notes that the GCMS was the decisive factor due to which "For most of the Viking scientists, the final conclusion was that the Viking missions failed to detect life in the Martian soil. One of the designers of the Labeled Release experiment, Gilbert Levin , believes his results are a definitive diagnostic for life on Mars. This was not true of the Martian soil; on Mars, the second and third nutrient injections did not produce any further release of labeled gas.
The Phoenix mission landed a robotic spacecraft in the polar region of Mars on May 25, and it operated until November 10, One of the mission's two primary objectives was to search for a "habitable zone" in the Martian regolith where microbial life could exist, the other main goal being to study the geological history of water on Mars. The lander has a 2. There was an electrochemistry experiment which analysed the ions in the regolith and the amount and type of antioxidants on Mars. The Viking program data indicate that oxidants on Mars may vary with latitude, noting that Viking 2 saw fewer oxidants than Viking 1 in its more northerly position.
Phoenix landed further north still. The analysers also indicated the presence of bound water and CO 2. This suggests a severely arid environment, with minimal or no liquid water interaction. The Mars Science Laboratory mission is a NASA project that launched on November 26, , the Curiosity rover , a nuclear-powered robotic vehicle, bearing instruments designed to assess past and present habitability conditions on Mars.
Mount Sharp ,     on August 6, On 16 December , NASA reported the Curiosity rover detected a "tenfold spike", likely localized, in the amount of methane in the Martian atmosphere. Sample measurements taken "a dozen times over 20 months" showed increases in late and early , averaging "7 parts of methane per billion in the atmosphere.
Some of the main reasons for colonizing Mars include economic interests, long-term scientific research best carried out by humans as opposed to robotic probes, and sheer curiosity. Surface conditions and the presence of water on Mars make it arguably the most hospitable of the planets in the Solar System , other than Earth. These technologies combined with the vast natural resources should enable, pre- and post-human arrival ISRU to greatly increase reliability and safety and reduce cost for human colonization of Mars.
From Wikipedia, the free encyclopedia. For other uses, see Life on Mars disambiguation. For the space mission, see ExoMars. Historical map of Mars from Giovanni Schiaparelli. Mars canals illustrated by astronomer Percival Lowell , Mars - Utopia Planitia Scalloped terrain led to the discovery of a large amount of underground ice enough water to fill Lake Superior November 22,   . Viking spacecraft biological experiments. Artist concept showing sand-laden jets erupt from geysers on Mars.
Close up of dark dune spots, probably created by cold geyser-like eruptions. Planetary protection and Interplanetary contamination.
Mariner Crater, as seen by Mariner 4 in Pictures like this suggested that Mars is too dry for any kind of life. Streamlined Islands seen by Viking orbiter showed that large floods occurred on Mars. The image is located in Lunae Palus quadrangle. Methane measurements in the atmosphere of Mars by the Curiosity rover August to September Methane CH 4 on Mars - potential sources and sinks. Comparison of organic compounds in Martian rocks - Chlorobenzene levels were much higher in the " Cumberland " rock sample. Detection of organic compounds in the " Cumberland " rock sample. The Search for Life on Mars.
Origin of Life Gordon Research Conference. Archived from the original on June 4, Archived from the original on September 12, Retrieved September 12, The Emergence and Maintenance of Life". Protostars and Planets V: Archived from the original on January 28, Archived from the original on January 29, Archived from the original on February 14, Retrieved September 6, Explicit use of et al. Retrieved 8 July Archived from the original on July 6, Retrieved June 7, You Read It Here First". Archived from the original on October 1, Retrieved October 1, A critical examination of Professor Percival Lowell's book 'Mars and its canals,' with an alternative explanation.
Life on Mars; The Complete Story. Implications from Initial Results". Dry deposition of analog soils on microbial colonies and survival under Martian conditions". Planetary and Space Science. Choi,, Charles May 17, Archived from the original on August 20, Archived from the original on June 12, Retrieved June 8, There is general consensus that extant microbial life on Mars would probably exist if at all in the subsurface and at low abundance.
Geology and Habitability of Terrestrial Planets. Archived from the original on July 3, Archived from the original on December 9, Goddard Space Flight Center. Archived from the original on September 14, Archived from the original on June 3, Archived from the original on June 15, Retrieved June 12, Retrieved 8 June Retrieved 7 June The New York Times. Conceivably, if life exists or existed on Mars, an icy moon, or some other planetary body, evidence of that life could be found, or is best preserved, in the subsurface, away from present-day harsh surface processes.
Hassler, Cary Zeitlin, Robert F. Archived PDF from the original on February 2, Magnetic Field and Magnetosphere". Encyclopedia of Planetary Sciences. Archived from the original on August 18, Archived from the original on August 30, Archived from the original on February 12, Archived PDF from the original on February 13, Surface of Mars Devoid of Life". Archived from the original on April 29, After mapping cosmic radiation levels at various depths on Mars, researchers have concluded that any life within the first several yards of the planet's surface would be killed by lethal doses of cosmic radiation.
Lunar and Planetary Institute. Archived PDF from the original on October 6, Bacteria or spores held dormant by freezing conditions cannot metabolise and become inactivated by accumulating radiation damage. Recovery of viable cells cryopreserved within the putative Cerberus pack-ice requires a drill depth of at least 7. Archived from the original on February 21, That's because any bacteria that may once have lived on the surface have long since been exterminated by cosmic radiation sleeting through the thin Martian atmosphere. Retrieved 30 September International Journal of Astrobiology.
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Planetary Protection Subcommittee Meeting. Archived from the original PDF on February 28, Archived from the original on May 3, Comparative Climatology of Terrestrial Planets. Archived from the original on November 24, Retrieved November 23, Archived from the original on November 23, Archived from the original on June 6, Archived from the original on August 12, Water on Mars Announced 10 Years Ago".
Archived from the original on December 22, Retrieved March 7, Archived from the original on June 11, Archived from the original on November 22, Ancient Floodwaters and Seas on Mars". Archived from the original on January 4, An assessment of the observational evidence and possible fate". Journal of Geophysical Research: The water vapor stage produced a large burst of oxygen from the Martian soil. Even though no light shone on the soil during the experiment, the result was held out as possible evidence of microbial photosynthesis.
When the soil was wetted with the GEx liquid medium, carbon dioxide was rapidly absorbed from the atmosphere into the soil but no additional oxygen evolved. When a duplicate sample of the soil was heated as a control and then tested, it still produced the large pulse of oxygen upon humidification.
The GEx Experimenter and the Biology Team concluded that GEx had produced no indication of life, but of some chemical oxidant in the soil that reacted with water vapor to yield oxygen. The possibility that oxygen adsorbed on the soil from the sparse amount in the Martian atmosphere was released by the GEx vapor also was raised, but discounted because of the large amount of oxygen released in GEx.
These adsorbed gases are released from the soil by modest heating. The second peak comes from gases released on further heating of the soil to combustion temperature. This signal indicates the burning of organic matter formed during the test. If found, the second peak is the evidence for life. Horowitz and his Co-Experimenters. He had the PR instrument recount the faint signal for a full day to demonstrate that it was statistically significant above the background noise.
While the PR signal was above the background level, it was far short of being significant in indicating life. Indeed, tests of the PR on Earth, both before and after the test on Mars, showed even higher responses from control tests with sterilized soils, despite the presence of the UV filter that had been installed to prevent false positives. Thus, the PR experiment gave no evidence for life. Nonetheless, the PR was a very important experiment which, until now, has not been given due credit. It confirmed on Mars that—as in the PR tests on Earth—organic matter is formed in the sunlit atmosphere and, even under the continuous shining of the UV light, accumulates in the soil where the Viking GCMS should have found it!
Had these gases not been incorporated into organic matter, they would have been blown out of the test cell during the first peak heating cycle. And, because of mechanical and design problems, it had to perform sample acquisition twice before Klaus Biemann felt the instrument had obtained a sample. As stated, the Viking scientists all felt certain that there were organic compounds on Mars. Thus the mission of the GCMS was not to detect them, but to identify them. Our LR group hoped that compounds implicating life would be found. When the analysis was finished, the results astonished everyone.
No trace of Martian organic compounds was found! However, the GCMS had problems which raise questions about the validity of its findings. It could not detect some organic matter of biologic origin in soils only sparsely populated with microorganisms. Mechanical problems on Mars resulted in difficulty in obtaining soil samples. The only evidence for samples was the observation that the sampling arm had scraped a small ditch in the soil to obtain the sample.
However, there was no way to tell whether that sample made its way through the distribution box, which received it, and then into the tiny ovens of the GCMS. And, if it did, the amounts that entered the ovens were uncertain. It finally was decided that the GCMS had obtained samples because of the amounts of water and carbon dioxide that evolved during the heating of the samples.
However, carbon dioxide constitutes 95 percent of the Martian atmosphere, and that atmosphere daily reaches percent relative humidity. Since frost was deposited on the surface daily, it also might have been deposited into the oven and sampling train of the GCMS, along with any carbon dioxide that had dissolved in the water vapor.
To what extent these possible deposits might have figured in the GCMS results, particularly if no sample of soil had been obtained, is unknown. The easy and cautious way out was apparent. The LR had detected inorganic chemical s , not life. Once set, that stage has never been changed. Simulations of the LR Results. In the twenty years since Viking many attempts have been made in various laboratories to duplicate the LR Mars results by nonbiological means. Our own laboratory spent three years in this effort.
Hydrogen peroxide, superoxides, metalloperoxides, peroxide complexes, UV light, and ionizing radiation were tested against Mars analog soils prepared by NASA based on Viking analyses of Martian soil, various clays, minerals, and other surrogate soil substrates. We applied a wide range of environmental conditions to the test procedure. LR radioactive solution and its single components were applied to the samples in a Viking-type LR instrument. A wide range of control regimens was used.
Under extreme conditions unrealistic for Mars we were able to force positive results. However, no simulation of the Mars LR data could be produced in any of our experiments or those of others when materials and conditions known to obtain on Mars were used. We have published on all of our efforts and on those of others that have been published or otherwise come to our attention. A plausible reproduction of the Mars LR data by nonbiological means remains to be demonstrated.
Generally reddish brown to brown, the landscape contained areas of ochre, yellow, and olive. Most surprising to me were olive to yellow-green to greenish colored areas on many of the rocks. One night I made the discovery that, on some of the rocks, these colored areas appeared to show changes in pattern and coloration from Martian year to year. I thought it was the second time I had discovered life on Mars! Analysis of the six channels of digital information comprising each Viking image—red, blue, green, and three near-infra red frequencies—showed these spots on the rocks to be the greenest objects in the entire field of view.
Thinking that the spots might look like lichen, on one trip I brought some rocks bearing patches of lichen from Maryland to JPL. I placed the rocks in the Viking 1 simulated landing site. The pictures were taken under the simulated Martian light bathing the scene. They were processed in an identical manner to those obtained on Mars. The digital spectroscopic analysis showed that the lichen on the rocks were the greenest objects in view.
Furthermore, the digital values of the color, hue, and saturation were very close to those for the greenish spots on the Mars rocks. Publication of this information in a technical paper had the reverse of the action I anticipated.
Instead of supporting the LR biological interpretation, the publication was viewed as a desperate, non-scientific ploy. First, it was widely denied that any greenish coloration showed on the photographs! Next, I was chastised for supposedly intimating that there were lichen on Mars by claiming to have found green areas. He subsequently wrote and published a report on the finding of greenish colored soil and markings on the rocks on Mars. Wary of the sinkhole that awaited biological references to Mars, he made no mention, among the many possible origins he cited for the coloration, of any biological possibility.
He even was careful not to reference our earlier paper, nor credit my having called his attention to the colored spots and areas. However, it only has been since publication of his report that the presence of green spots on Martian rocks has become accepted. Recent renderings of the Martian landscape, once again, look very much like Arizona—as demonstrated by the carefully prepared image serving as the cover on the book Mars, published in The perceived lack of liquid water on the surface of Mars has led many scientists to conclude that life could not be sustained there and, therefore, the LR results must be ascribed to chemistry.
I do not believe the answer to be as simple as that didacticism. As with so many other questions put to Mars, it does not give a straightforward answer with respect to liquid water. If the total atmospheric pressure exceeds 6. However, if the total atmospheric pressure is below 6. Atmospheric pressure on Mars varies between approximately 6 and 10 mb.
Thus, at times when 6. Temperatures of the sampling arms in contact with the soil were recorded at both Viking landing sites. The temperatures of the arms rose as the Sun rose to and a little beyond its zenith. The temperatures of the arm at the Viking 2 site reached degrees Kelvin 0 degrees Celsius, the melting point of water and stayed there for a while. That means that liquid water was present under the arms. When water transitions from solid to liquid, just before it melts, extra heat the heat of fusion is required before the temperature can continue to rise.
This pause in the temperature rise is what Viking recorded—proof of liquid water. It is true that the metal sampling arms absorbed and stored more heat from the Sun than the soil would otherwise. However, it is quite likely that dark rocks, and perhaps dark soil, at the sites of both Landers act the same way. They could supply liquid water to microorganisms if only for a brief period daily. Mars microorganisms may well have adapted to garner needed water in this fashion. Furthermore, a new book Water On Mars, M. Carr, reports that the Viking Orbiters found surface temperatures reaching degrees Kelvin at the summer solstice at 1 P.
Viking also reported temperatures exceeding degrees Kelvin 98 degrees Fahrenheit in the northern hemisphere where both Vikings landed. At the other extreme is the possibility that Martian organisms may be able to obtain their water from the atmosphere, as has been reported for some lichen on Earth. While the Martian atmosphere is only about one percent of ours, both Viking sites showed high relative humidities, reaching percent nightly.
Even if the water vapor were in the form of tiny ice crystals, these would deposit on the organisms. The organisms might have learned to store energy from the Sun to melt the crystals and absorb the liquid, or, as many Earth microorganisms do to prevent freezing, Martian organisms might make antifreeze. Finally, ice crystals have been shown to participate in chemical reactions, such as in the atmospheric destruction of ozone by chlorofluorohydrocarbons CFC , which is responsible for our ozone hole.
This process may be used by microorganisms on Mars and, perhaps, on Earth, too! In sum, there is evidence for liquid water on Mars. Our knowledge of the water issue—on Earth or Mars—is too uncertain to be used as an absolute barrier to life on Mars. When meteorite ALH , believed to have come from Mars, was found to contain fossils indicating life, the news startled the world. Once again, the question of life on Mars became front-page news. Analysis indicated the meteorite to be approximately 3. By then the planet had had time to cool and become environmentally conducive to life.
Liquid water is believed to have been abundant on Mars at that time. This history closely paralleled that of Earth, which is believed to have given rise to living organisms within the first billion years of its formation. Since the meteorite had left Mars before the serious environmental changes inimicable to life occurred, it was presumed that the life present three and one-half billion years ago had since become extinct.
This scenario greatly stimulated the concept of searching for microbial fossils on Mars rather than extant life. But Mars was not done with teasing humans. This meteorite not only confirmed the biological organic evidence of the earlier one, but was estimated to be less than , years old!
In terms of the planetary history of Mars, this was modern times, well after the drastic environmental changes on Mars which had been widely advertised as proof that the Viking LR could not have detected life. No one has offered to explain how the meteor that impacted Mars to launch EETA on its long journey to Earth found a precious oasis! Nor have the oasis proponents addressed a recent study which finds that material ejected from a planet by meteoric impact comes from near the surface not from the depths proposed for such oases And the leaders of the fossil search press on with no announced thought that might link the recent findings to the LR results!
Darwin must be spinning in his grave at the thought that the modern descendants of his discipline believe that life existing on Mars during its recent era would not have survived to the present. However, they do not deny that early Earth life was faced with a much more desperate situation. When oxygen first appeared, produced by photosynthetic organisms, this gas was intensely toxic to all other life forms. However, life managed to convert that adversity to advantage. Expansion of the Life Envelope. While the direct investigation of life on Mars has been at a standstill for the twenty years since Viking, knowledge about life on Earth has increased to an astonishing degree.
Microorganisms, large anchored tubular worms, and fish, all previously unknown, have been found living in deep ocean trenches in lightless waters at temperatures of several hundred degrees Celsius and under pressures of thousands of pounds per square inch. Microorganisms frozen deep below the surface for millions of years have been resuscitated instantly when brought to the surface.
Microorganisms have been found growing in cooling waters irradiated by nuclear reactors. A new kind of microorganism, capable of living on rock and water, has been found in deep sunless pools. Why should we expect life on Mars to have done less? Perhaps the most important accomplishment of the analysis of the two life-bearing meteorites is their proof of the theory of Panspermia advanced by Svante Arrhenius in the nineteenth century.
This Nobel Laureate in chemistry envisioned that life traveled through space, inoculating planet after planet. Whether the two SNC meteorites come from Mars, or not, matters little in this case. What matters most is that they do bear evidence of biology from someplace other than Earth! This finding defeats the ultimate argument of those opposing acceptance of the LR data—that the origin of life is such a complex process, still not nearly understood, that to suppose it happened on Mars is the most far-fetched explanation of the LR data possible.
The meteorites show that we no longer have to assume that life on Mars arose there! Life, at least microorganisms, can ride the Cosmos. The way to preserve microorganisms indefinitely no time limit is yet known, but it exceeds millions of years is to freeze them. In the laboratory we freeze and dry them. They are readily resuscitated when placed back into an environment favorable to them. Space travel provides the best freeze-dry process available! So, microorganisms, once formed somewhere, can hitch rides for millions of years!
Of course, while freeing up the LR data, this new information merely pushes back the problem of how life began somewhere. Between and , Pat Straat and I contended in published papers and oral statements that a biological interpretation of the LR results was possible. Each of the reasons supporting a non—biological interpretation of the LR Mars data has now been shown deficient. The demonstrated success of the LR in detecting microorganisms during its extensive test program with its record of no false positives can no longer be denied.
New evidence, together with the review of the old, leaves the biological interpretation standing alone. The scientific process forces me to my new conclusion: The conclusion that the Viking LR results and all available relevant evidence point to the existence of microorganisms in the soil of Mars raises the question of what type of microorganisms they might be, Several possibilities are evident. Species on Earth are reported to survive on water obtained in vapor form, to endure Mars-like cold, and to grow on, even inside, rocks.
The discovery and analysis of the Martian meteorites, if confirmed, would make it extremely likely that Earth and Mars have exchanged material frequently. As stated, space conditions are very good for the preservation of any microorganisms inside the ejecta. Since lichen are present within rocks on Earth, they, but not only they, make a good candidate for interplanetary travel.
The two symbiotic components of lichen are algae and fungi. They might also be widely distributed as individual species, as might a great variety of other species. As pointed out earlier, those niches on Mars are much less severe than on Earth. Even if that unlikely scenario of discrete oases were true, those oases might still have supplied living organisms to the LR.